An interruption of communication within the flight control system caused the December crash of a Boeing A160T Hummingbird unmanned helicopter, but what triggered the feedback failure is not known because the air vehicle was destroyed.
Only two more flights are needed to complete the Phase 1 demonstration begun in August 2003, programme manager Phil Hunt told an IDGA unmanned air vehicles conference in Washington DC. The goals still to be demonstrated are hover out of ground effect at 15,000ft (4,600m) and 18-20h endurance with a 135kg (300lb) payload.
"The mechanism of failure is understood, but the trigger is not known," says Hunt. Boeing has taken mitigating actions, but the A160T has single-string avionics with no redundancy and the FAA must approve its return to flight because tests are being conducted in civil airspace around Victorville, California.
Other demonstrations involving the A160T carrying various advanced sensors are planned to be conducted in restricted airspace. Flights with a foliage-penetration radar under DARPA's Forester programme are planned for July-August. The US Army and Navy may also use the A160T for other demonstrations, Hunt says.
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